I never do something away out of my collection before I know for sure, it is fake. I will continue looking and talk to people until I know for sure whether this armband is real or fake !!! This is what i love on this hobby.
I started my hobby with collecting NSDAP party badge, i have 25 badge which 5 badges of them where I knew not sure if they are real. I have always keep the 5 badges because I enjoy it to further investigate of this. After a few years there came a
book called "party badge" on the market (from Jo Rivett)

That book is so awesome that i have discovered that 3 of the 5 badges are real !!! (your book is awesome)
I hope in the future to find out whether the armband is real or fake !